Demolition as the name implies, is the bringing down or tearing down of buildings, structures, and other man-made erections thereof by pre-planned and controlled methods. Some people do not notice the difference or contrast between Demolition and Deconstruction. Deconstruction involves the bringing down of buildings and structures, preserving valuable components or elements in order to use them later.
Who is a Demolition Contractor?
A demolition contractor is an approved and certified person or company. It means someone who has all the qualifications and experience required for the demolition of structures. This individual or company is/are registered with the government of the country or state.
When the amount for Demolition work is above $250,000 or more, the work is considered a demolition project for which extra duties apply to the contractor. There can only be one demolition contractor for a project. It is also possible that the demolition professional may be appointed as the principal contractor.
Methods Of Demolition
The methods of demolition can be very vital in the health and safety of the workers and general public. The demolition method will depend on factors like the type of construction, and location. Buildings and structures should generally be demolished in opposite order to their construction, that is, by sequential demolition.
The methods of demolition include:
Manual demolition involves any method where hand tools such as jackhammers, sledge hammers and picks are used.
Manual demolition has many of the dangers that are present in other major demolition activities including unpredictable collapses, falls, falling objects, manual handling and exposure to noise, dust and hazardous chemicals.
Mechanical demolition includes the use of mechanical mobile plants, such as excavators, cranes, loaders and bulldozers. There may be a combination of hand and mechanical demolition methods. All mechanical mobile plants used for demolition must be fitted with an appropriate blend of operator protecting devices. Operator protecting structures should be lifted to the appropriate standard that eliminates or minimizes the risks.
Demolition should be strategic and sequential. That is, a structure should normally be demolished in the opposite order to which it was built.
Induced collapse involves the sequential removal of main structural members and the application of a force in order to result in the controlled collapse of all part of a building or structure. The services of a demolition contractor should be sought before this method is used. This method should only be used on detached, isolated structures on reasonably level sites. There must be enough space for debris to fall.
Construction work that involves the use of explosives is defined as high risk construction work and the demolition company & building regulatory authority of the intended country or state should be adequately prepared before this work commences.
Explosives must not be used to induce the collapse of any structure unless approved by the regulatory authority.
Explosives must only be used by a capable person who is approved in the use of explosives and has experience in the work to be commenced.
Prior to carrying out any building demolition, detailed building evaluation by means of surveys and suitable assessments shall be required. The surveys shall include a building survey and a structural survey with photographs or videos taken for future reference. Based on the findings of these surveys, a demolition plan shall then be prepared and submitted to the buildings department for approval. The demolition plan must also be attended by a report together with structural calculations assessing the stability of the building to be demolished and all affected buildings, and structures.
Site safety features shall highlight safety of the public, mostly the pedestrian and vehicular traffic and the end-to-end properties. Proper safety features shall be designed by the demolition contractor to ensure that the demolition can be carried out safely and the site workers are protected. The demolition contractor shall carry out the demolition work including precautionary measures in accordance with the approved plans and other related documents, and provide continuous supervision to the work being done. The precautionary measures include:
Hoarding and Covered Walkway
The main purpose of hoarding and covered walkway is to provide safety of the public during the construction or demolition of buildings. Generally, hoarding segregates the demolition site from the public, thus preventing unauthorized access and intruding. The covered walkway, in combination with catch platform, provides extra safety to the pedestrian traffic against falling debris. The demolition contractor shall design them to suit individual site conditions.
The design aim of the catch fans is to catch small pieces of building wreckage that passes through the protective screen and net, and the catch fans are not intended to collect large pieces of building wreckage which should have been collected by the protective screen or net. A small piece of wreckage could be catastrophic after gaining enough kinetic energy through falling great altitudes.
Temporary supports to the structure or the elements of the structure being demolished shall be provided when the whole or any part of the structure is exposed to extra loading resulting from the demolition activities, movement of powered mechanical plants or wreckage build-up.
Temporary Propping System
Manufactured propping system may be used to support the operation of the mechanical plant, or other loading during the demolition process on a suspended floor.
Services Offered By A Demolition Contractor
There are various services offered by a demolition contractor in the field of demolition. These services depends on the location, and type of structure erected and also the tasks required by the clients. These services include
How To Find Your Ideal Demolition Contractor
Demolition contractors can be found locally depending on your state. There are so many online directories which can help you find qualified and certified demolition contractors. Of course, needless to mention, the contractor needs to have been in the industry long enough and have gathered lots of client feedback. You may also affirm the legality of the contractor’s business by asking about the status of their license and insurance.